New hardware, coupled with enhanced software, should begin to improve on the 40 percent crash reduction that earlier versions achieved

Tesla CEO Elon Musk says that the latest software for his company’s AutoPilot self-driving package will better the 40 percent reduction in crashes that earlier versions have already shown.

Since October Tesla has been offering new hardware, including sensors, as well as new releases of software to exploit that hardware’s capabilities. Last week it began uploading what it calls an enhanced mode of the software, and now it is making that software operational in the cars. The company didn’t speculate on how much today’s release might improve safety, but Musk said that the final effect would be massive.

“Our target is a 90 percent reduction [in crashes] as the software matures,” he posted on Twitter.

Musk was expanding on a report published last week by the U.S. National Highway Safety Administration that not only exonerated AutoPilot of having a role in a fatal crash in Florida last summer but added that airbag deployments indicated that the crash rate had fallen nearly 40 percent, to 0.8 per million miles driven, down from 1.3 per million miles before the original version of AutoPilot was installed.

The fatal crash had cast a pall over Tesla’s system, prompting some critics to say that the company had overpromised simply by choosing the name AutoPilot. Tesla acknowledges that AutoPilot is not—yet—a truly autonomous system but rather a package of driver-assistance features, such as emergency collision avoidance, lane keeping, and active cruise control.

On Saturday Musk warned customers who were about to have access to the newly downloaded software package that there might be a need to adjust the hardware—specifically the angle of the cameras.